There are wheel loaders and other work vehicles that comprise a torque converter device having a torque converter and a lockup clutch. The torque converter device transmits the drive force from the engine to the travel device via the torque converter when the lockup clutch is in a non-connected state (this state is hereinafter referred to as “torque conversion travel”). When the lockup clutch is in a connected state, the torque converter device transmits the drive force from the engine to the travel device via the lockup clutch (this state is hereinafter referred to as “lockup travel”). Switching the lockup clutch between the connected state and the non-connected state is automatically carried out by a controller. The controller switches the lockup clutch between the connected state and the non-connected state when, e.g., the vehicle speed reaches a predetermined switch speed (see Japanese Laid-open Patent Application No. 2009-103258).